Wood grinder



w 4 .ff

P. PRIEM WOOD -GRINDER Filed June 12 W A/r// 4// MayV 6. 1924.

Patented May 6, 1924.

UNITED S'TTYES Pasteur OFFICE.

PAUL PRIEM, OF HEIDEN-HEIM-ONfTHEfBRENZ, GERMANY, ASSIGNOR TO AMERICAN VOITH CONTACT ,COMPANYQ INC., NEW YORK, N. Y., A CORPORATION OF NEW Yonx. n

woon Gurunnn.

To all whom t may concern.'

Be it known' that I, PAUL PRIEM, a citizenof the Republic of Germany, and residing at Heidenheim-on-der-Brenz, Germany, have invented certain new and useful Improvements in Wood Grinders, of which the following is a specification.

In continuously operating wood grinders, in which feed devices press against the sides of the charge of blocks and advance it against the grind stone, `I have observed that only the blocks vwhich are in direct engagement withfthefeed devicesthat is to say, only those at the sides ofthe charge mass,--are forced againstv the grind stone with the desired pressure. `The blocks in the middle of the charge mass, which are not directly engaged by the feed devices, do not receive sufficient pressure from the latter for the most efhcient operation of the grinder. This difficulty cannot be remedied by merely increasing the height of the hopper and of the chargey mass within it--even for example, to the height of sixty feet. Even under such conditionsthe action of the grind stone on the blocks in the middle of the charge is incomplete, because of the lack of necessary pressure at this point. The efficiency of th'egrinder is seriously influenced by this condition, since the pressure of the blocks against the stone is really the controllingfactor in determining Ithel out-A put of the machine. 'f

I have met this difliculty according tothe present invention, by increasing the feed pressure on the interior ofthe charge by increasing the lateral pressure ofthefeed devices against the sides of the block jmass. As a lconsequence-of the increased lateral pressure ofthe feeders, the frictional engagement between the `blocks of the charge is so increased, that the gripy of the feeders on the sides of the charge is transmitted to the interior of the mass, andthe latter, as well as the marginalareas thereof, is forced against the grinder with the ydesiredpressure. y

Several ways of accomplishing this are shown in the accompanying drawings, in which- Figs. 1 and 2 are vertical sections through feed hoppers in which my invention is lembodied in different manners; l

of `feedchains1l,'5 andf, whichmay be arranged adjacent,r the front and back` walls of the' hopper, and areprovide'dlwith feed pallets or `teeth in well' understood-manner. The feed chains pass through'slots inthe walls of the hopper' so thatftheir ,inner and downward-travelling reaches engage the' adj acentsides of the charge. The feed chains 5 pass over' sprockets 8 and 9, which may be driven in any suitablev manner.` Fast 'on'the spindles of the sprockets )9 are smaller sprockets lO, which drive'the chains 6, the lower ends of which pass over sprockets l1. Inasmuch as the chains 6 aredriven by the smaller sprockets' 10,' their speed is less than that of the uppermost chains 5.-- Similarly, the sprockets 11 have fast therewithsmaller sprockets 12' which drive the low'ermost chains 7 which, at their lower ends, engage the sprocketsv 13. The .chains 7 are thus driven still slowerl than the chains 6; The

speeds of the three feed chains v5, 'f5-and 7 are consequently progressively slower,y and' the feed of the bloclrmass is'simi-larlyv progressively less as it approaches thefstone 3. During their drive, the feed v'chains bear against the inner faces of the hopper wall sections 60, which may befeither rigid'or yieldingly heldin position,f and support the feed chains. As a result `of the greater speed at which the upper chains 5 and 6- are driventh'e more' rapidfeed of the charge at this p oint compacts thel chargebelow, and

thus increases the frictionalengagement ybetween the blocks, and the effectiveness with which the interior of the charge is pressed against the grind stone. Ofcourse' thenumber of feed chains, and their extent, may be varied as desired.

In Fig. 2 the increased pressure on the interior of the charge in the neighborhood of the grind stone is accomplished by reducing the diameter of the hopper adjacent the stone in the area in which the feed devices work. As a result, the compactness of the charge adjacent the stone is increased, with accompanying increase of eective feed pressure, especially upon the blocks in the interior of the mass which are forced by the feeders against the stone. The effective operation of the stone is greatly increased by this simple expedient.

For this purpose the feed chains 14 are engaged by sprockets 15 and 16, driven in any suitable fashion. The pressure of the feed chains against the blocks is accomplished by press plates 17, which are pivoted on trunnions 18 at their upper ends. At their lower ends, the plates are engaged at 19 by rods 2O of pistons 21 working in cylinders 22, to which air or liquid under pressure is introduced through pipes 23, so that the lower ends of the plates 17 are forced by the pistons against the charge.

Instead of pressure cylinders, heavy springs 45 may be substituted, as indicated in Fig. 3.

lvhichever arrangement is employed, the press plates 17 are forced against the charge in the hopper, in thoroughly practical manner, and the pressure may be regulated as desired, either by varying the pressure of the liquid or air admitted to the cylinders 21, or by varying the stress of the spring 45.

It is not necessary that the reduction of the hopper cross section be gradual and continuous, as in Figs. 2 and 3. It suffices, as shown in Fig. 4, to provide a constricted area at the point spaced somewhat above the stone. In this construction the increased compactness of the charge in the neighborhood of the stone is effected by shoes 24, against which slide the inner reaches of the feed chains, the shoes being drawn together by links 25 Connected at 26 to the pistons 27 of pressure cylinders 28 mounted on the sides of the hopper.

In Fig. 5 the compactness of the charge is increased at the stone by curving the lower portion 290i the hopper 4. 0n the concave wall of the curved portion 29 of the hopper, is arranged the feeder 30 which runs on sprockets 31 and 32. The inner reach of the feeder lies against the inner face of a curved press plate 33, which is pivoted at 34 at its upper end, while its lower end is forced inward by the heavy spring 35 against the blocks. A cooperating feeder 36 bears against the inner face of the convex sides of the curved lower end of the hopper, and runs over sprockets 37, 38 and 40, of which the intermediate sprocket 38 serves as the driving element. The plate 42, against the inner face of which the feeder travels, is stationary..` Obviously if Q1 represents the travel ofthe feeder 36 in a given time interval, the compression of the charge corresponds to the difference between the masses 7L and h2 with respect to the lateral projection of the distances lv.

Again, the compacting of the charge may be accomplished as indicated in Fig. 6, in which the feeders V47, ruiming over the sprockets 48 and 49, carry wedges 5() which, during their working travel, gradually vary their inclination from a downwardly angled position to a position more nearly horizontal. rIhus, if the wedges 50 at the outset of their working travelassume an angle of 609 from the horizontal, their speedy of advance may be so much greater with respect tothe speed of consumption of the blocks by the stone that as they approach the latter they assume an angle of only 30J to 45. The compacting of the charge thus increases as the wedges approach the stone and gradually assume a more nearly horizontal position.

Various other arrangements for accomplishing the same end will readily occur to those dealing with the problem, without departing from what I claim as my invention.

I claim- 1. In a wood grinder, a grind stone, an associated hopper for a charge of wood blocks, and feed means engaging the charge and operative to advance the latter at decreasing speed as it approaches the grind stone and while engaged by said feed means.

2. In a wood grinder, a grind stone, an associated hopper for a charge of wood blocks, and feed means engaging the charge and operative to progressively compact the charge and to advance the same at decreasing speed Y as the charge approaches the grind stone.

3. In a wood grinder, a grind stone, an associated hopper for a charge of wood blocks, and feed means engaging the charge and automatically operative to progressively compact the latter and to advance the same at decreasing speed as it approaches v the grind stone.

4. In a wood grinder, a grind stone, an associated hopper for a charge of wood blocks, endless feed means operating in the hopper and engaging the charge' for simultaneously advancing the latter at progressively reduced speed and laterally compacting the charge progressively as the latter is ad.- vanced at reducedspeed toward the grind stone.

5. In a wood grinder, a grind stone, an associated hopper for a charge of wood blocks, means engaging the sides of the charge for continuously and forcibly feeding the' latter against the grind stone, said feed means adjacent the grind stone serving to advance a portion of the charge in engagement therewith at a speed commensurate with the consumption of the charge .by the grindstone, and simultaneously to advance the charge at an accelerated speed at a point remote from the grind stone to effect a compacting action upon the charge in the neighborhood of the stone.

6. In a wood grinder, a grind stone, an associated hopper for acharge of wood blocks, a series of feed chains for continuously and forcibly feeding the charge against the grind stone, and means for driving the feed chains remote from the charge at higher speed than those engaging the charge in the neighborhood of the stone, the drive of the latter being at a speed, substantially commensurate with the rate of consumption of the charge by the stone.

7. In a wood grinder, a grind stone, an associated hopper for a charge of wood blocks, a series of feed chains engaging the charge and driven at different relative speeds, the feed chains remote from the stone being driven at higher relative speed than the feed chains adjacent the stone.

8. The method of continuously feeding a charge of wood blocks to a grind stone which comprises advancing the portion of the charge in engagement therewith toward the stone at progressively' diminishing speed, the speed of the feed in the neighborhood of the grind stone being substantially commensurate with the consumption of the charge by the stone.

9. The method of continuously feeding a charge of wood blocks toward a grind stone, which comprises advancing and simultaneously laterally compacting the charge, and effecting the lateral compacting action upon the charge as it a proaches the stone by diminishing the speed of the advance of the charge.

10. The method of continuously feeding a charge of wood blocks in a wood grinder or the like, which consists in subjecting the charge at points differently spaced from the stone to feed thrusts exerted at dierent speeds, the thrusts at the areas remote from the stone exceeding in speed the feed thrusts in the neighborhood of the stone. j

11. vIn a wood grinder, a grind stone, an associated magazine for a charge of Wood blocks, together with a series of feed chains arranged along each of two opposite sides of the magazine, each successive chain of each series acting substantially as a continuation of the preceding chain of the series to advance the charge continuously toward the grind stone, and means for so driving the chains at each side of the magazine that they cooperate to increase the pressure in the interior of the charge v*as it approaches the grind stone.

12. In a wood grinder, a grind stone, an associated magazine for a charge of wood blocks, together with a series of feed chains arranged along each of two opposite sides of the magazine, the successive chains of each series overlapping at their adjacent ends and serving to advance the charge continuously toward the grind stone, and means for so driving the chains at each side of the magazine that they cooperate to increase the` pressure in the interior of the charge as it approaches the grind stone.

In testimony that I claim the foregoing asv my invention I have signed my name.

PAUL PRIEM. [n 8.]

Witnesses: v

BERTOLD A. BRAUN, M. W. ALTAFFER. 

